title: Flow cytometry total cell counts: a field study assessing microbiological water quality and growth in unchlorinated drinking water distribution systems.
abstract: The objective of this study was to evaluate the application of flow cytometry total cell counts (TCCs) as a parameter to assess microbial growth in drinking water distribution systems and to determine the relationships between different parameters describing the biostability of treated water. A one-year sampling program was carried out in two distribution systems in The Netherlands. Results demonstrated that, in both systems, the biomass differences measured by ATP were not significant. TCC differences were also not significant in treatment plant 1, but decreased slightly in treatment plant 2. TCC values were found to be higher at temperatures above 15°C than at temperatures below 15°C. The correlation study of parameters describing biostability found no relationship among TCC, heterotrophic plate counts, and Aeromonas. Also no relationship was found between TCC and ATP. Some correlation was found between the subgroup of high nucleic acid content bacteria and ATP (R (2) = 0.63). Overall, the results demonstrated that TCC is a valuable parameter to assess the drinking water biological quality and regrowth; it can directly and sensitively quantify biomass, detect small changes, and can be used to determine the subgroup of active HNA bacteria that are related to ATP.
authors.affiliation: Section Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, The Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: Liu
authors.forename: E J
authors.initials: EJ
authors.lastname: Van der Mark
authors.forename: J Q J C
authors.initials: JQ
authors.lastname: Verberk
authors.forename: J C
authors.initials: JC
authors.lastname: Van Dijk
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000333:Aeromonas / Q000302:isolation & purification; D001419:Bacteria / Q000254:growth & development*; D018533:Biomass; D015169:Colony Count, Microbial; D060766:Drinking Water / Q000382:microbiology*; D005434:Flow Cytometry / Q000379:methods*; D054879:Halogenation; D052836:Heterotrophic Processes; D009696:Nucleic Acids / Q000378:metabolism; D013696:Temperature; D014871:Water Microbiology / Q000592:standards*; D018508:Water Purification; D060753:Water Quality / Q000592:standards*; D014881:Water Supply / Q000592:standards*
chemical_list: D060766:Drinking Water; D009696:Nucleic Acids; D000255:Adenosine Triphosphate